Since introducing reusable bags three months ago, the country's two largest supermarkets have prevented an estimated 1.5 billion bags from entering the environment.

Three months on, the radical change has translated to an 80 per cent drop in the consumption of plastic bags nationwide, according to the National Retail Association (NRA).

"Indeed, some retailers are reporting reduction rates as high as 90 per cent," NRA's David Stout told AAP.

Mr Stout said the ban was a "brave" move from the major supermarkets and it's paving the way for smaller businesses, who typically can't afford to risk the wrath of their customers, to follow suit.

"They're (supermarkets) obviously seen as the product stewards so a lot of people will come back to them," Mr Stout said.

"Obviously the best thing for smaller businesses is to either engineer out the bag completely or have the customer pay," he said. "They should be able to consider that strategy without fear of backlash."

Mr Stout said that everyone delivering things in a package need to take responsibility for what they deliver it in.

"I think there's going to be a lot more pressure on all of us to be more aware of what we consume," he told AAP.

NSW is the only state or territory in the country without at least a commitment to ban single-use bags, with Victoria vowing to phase them out in 2019.

"The NSW Government welcomes the proactive step taken by large retailers to phase out single-use plastic bags and provide soft plastic recycling bins in all stores without the heavy hand of legislation," a spokesperson for Environment Minister Gabrielle Upton told The New Daily in July, a week after Coles and Woolies enforced the ban.

Both Coles and Woolworths committed to a June 30, 2018 deadline for removing single-use plastic bags last year. Picture: AAP Image/Peter RAE

But Mr Stout said it's time NSW upped its game and quit relying on the supermarket ban to do the work.

"We're still seeing a lot of small to medium bags being used, especially in the food category, and while I get some comfort that the majors have done this voluntarily I think there still needs to be a ban in place," he said.

"For business, for the environment, for the consumer and of course even for councils which have to work to remove these things from landfills, there's a multitude of benefits on a whole to doing this."

He is hopeful major retailers will continue to lead the charge towards a more sustainable industry and move to ban other single-use packaging options.

Target and Kmart - both part of Coles' Wesfarmers - have committed to stop providing single-use bags by 2019.